In the sharpening of cutting tools, such as milling cutters or gear hobs, the size and geometry of the tool are factors that influence the diameter of the grinding wheel best suited for tooth profile grinding. As the number of gashes (flutes) increases and/or the diameter of the hob or milling cutter gets smaller, the indexing space from tooth to tooth along a helical thread lead or non-helical circumferential path gets smaller thereby requiring a smaller grinding wheel to radially relieve a tooth profile to its designed length and not interfere with the tip of the next tooth along the grinding path.
Tooth profile depth also dictates the minimum diameter wheel that can be used so that the trued/dressed minimum root diameter of the wheel is always greater than the outside diameter of the grinding spindle when the spindle is parallel to the axis of the workpiece being ground.
In most cases, as the need arises for grinding wheels having different outside diameters (in order to maximize metal removal rates without introducing tooth to tooth interference), so does the need to provide a grinding spindle of appropriate size so as to maximize the stiffness of the spindle. However, on conventional grinding machines, exchanging the grinding spindle is an arduous and time consuming task. On account of this, many tool manufacturing facilities employ a plurality of grinding machines of varying spindle and grinding wheel sizes. On the other hand, in an effort to minimize the expense of multiple machines, some profile grinding processes are compromised by utilizing inadequately sized grinding spindles for certain grinding wheel diameters.